The Development And Application Of The Headspace Odor Analyzer

At present,the traditional gas detector includes two types:diffusion type gas detector and pump suction gas detector.The sampling mode of diffusion type gas detector is that the sample is spreading in air and react with the gas sensitive materials by contract.while the pump suction gas detector have a air pump and use the air pump to collect the sample gas.The diffusion type gas detector is easily influenced by the environment such as temperature,humidity and airflow disturbance,it can't be used under the conditions of low pressure.Because of the air pump and the pipe,the pump suction gas detector will have a complex structure.The equipment is expensive and big.In order to overcome the shortcomings of the common gas detector,we design a novel headspace odor analyzer which is based on metal oxide gas sensor arrays.The sampling way is a static sampling method, which avoids the influences of airflow. Moreover, the analyte concentration of the headspace is constant. Besides, without pump and pipelines, the cost of the system is low and the structure is simple. While the sensor is direct exposed to the volatiles, it eliminates the concentration deviation and cross interference that arise from the adsorption on the inner wall of pipelines. The characteristics of cheap, convenient and quantitative make this sampling way perfect to be applied to on-site analysis.The research design a few experiments,using the novel headspace odor analyzer to test the milk and 13 kinds of traditional C hinese medicine.we count the colony forming units of the pure milk to make a connection between the info of flavor characteristic and national standard of milk spoilage.The correct classification rate of the headspace odor analyzer to discriminate thirteen species of herbs is 100% by Fisher discriminant analysis.the results show the application potential of the E-nose for on-site volatiles analysis.